thumb|The Revisionist Zionist Union
Revisionist Zionism is a form of Zionism characterized by territorial maximalism. Revisionist Zionism promoted expansionism and the establishment of a Jewish majority on both sides of the Jordan River. Developed by Ze'ev Jabotinsky in the 1920s, this ideology advocated a "revision" of the "practical Zionism" of David Ben-Gurion and Chaim Weizmann which was focused on the settling of Eretz Yisrael (Land of Israel) by independent individuals. Differing from other types of Zionism, Revisionists insisted upon the Jewish right to sovereignty over the whole of Eretz Yisrael, including Mandatory Palestine and Transjordan. It was the main ideological opponent to the dominant socialist Labor Zionism. Revisionist Zionism has strongly influenced modern right-wing Israeli parties, principally Herut and its successor Likud.
In 1935, after the Zionist Executive rejected Jabotinsky's political program, Jabotinsky resigned from the World Zionist Organization and founded the New Zionist Organization (NZO), known in Hebrew as Tzakh. Its aim was to conduct independent political activity for free immigration and the establishment of a Jewish State. In its early years under Jabotinsky's leadership, Revisionist Zionism was focused on gaining support from Britain for settlement. From the early 1930s, Jabotinsky believed that the United Kingdom could no longer be trusted to advance the Zionist cause, leading to a short-lived alliance with Fascist Italy. Both the Irgun and the Stern Gang, which emerged from it, were responsible for several attacks against the British to try to expel them from Palestine. After the White Paper of 1939 severely limited Jewish immigration to Palestine, just as the Nazis were gaining power, the Irgun and Lehi initiated campaigns against the British.
After the founding of Israel, control of the East Bank became increasingly less important in the ideology of Revisionist Zionism. Following the 1967 Six-Day War, when Israel occupied the West Bank and the Gaza Strip, Revisionism's territorial aspirations concentrated on these territories instead. By the 1970s, the legitimacy of the Hashemite Kingdom of Jordan was no longer questioned and in 1994, an overwhelming majority of Likud Knesset Members (MKs) voted for the Israel–Jordan Treaty of Peace. Jabotinsky attempted to get a motion passed to support an anti-Nazi boycott which was defeated 249 to 43. Jabotinsky became head of Betar in 1929, but the actual organization was founded by Aron Propes in 1923. Menachem Begin joined Betar in 1929 in Poland and was head of the national unit, which was the largest branch of Betar in the world.
The Herut party in 1948 won 14 seats in the 1949 elections.
When Begin finally came to power in the 1977 election, his overriding concern as Prime Minister (1977–1983) was to maintain Israeli control over the West Bank and Gaza.
In 1983, following criticism of the Israeli war in Lebanon in 1982 and the Sabra and Shatila massacre carried out by Israel's Lebanese Christian allies, Begin resigned as prime minister of Israel. By the late 1930s, Revisionist Zionism was divided into three distinct ideological streams: the "Centrists", the Irgun, and the "Messianists".
Jabotinsky later argued for establishing a base in the Yishuv and developed a vision to guide the Revisionist movement and the new Jewish society on economic and social policy centered around the ideal of the Jewish middle class in Europe. Jabotinsky believed that basing the movement on a philosophy contrasting with the socialist-oriented Labour Zionists would attract the support of the General Zionists.
In line with this thinking, the Revisionists transplanted into the Yishuv a youth movement, Betar. They also set up a paramilitary group, Irgun, a labour union, the National Labor Federation in Eretz-Israel, and health services. The latter were intended to counteract the increasing hegemony of Labour Zionism over community services via the Histadrut and address the Histadrut's refusal to make its services available to Revisionist Party members.
Irgun Tsvai Leumi
thumb|The emblem of the Irgun
The paramilitary organization of the Revisionist movement was called the National Military Organization, or the Irgun. The Irgun (short for , Hebrew for "National Military Organization" ) had its roots initially in the Betar youth movement in Poland, which Jabotinsky founded. By the 1940s, they had transplanted many of its members from Europe and the United States to Palestine.
The Revisionists split from the Haganah in 1931 because they opposed its domination by the Histadrut.]]
A group of fighters with particularly militant views in the Irgun formed an underground movement called "The Fighters for the Freedom of Israel" or the Stern Gang. On the topic of "transfer" (expulsion of the Arabs), Jabotinsky's statements were ambiguous. In some writings he supported the notion, but only as an act of self-defense, in others he argued that Arabs should be included in the liberal democratic society that he was advocating, and in others still, he completely disregarded the potency of Arab resistance to Jewish settlement, and stated that settlement should continue, and the Arabs be ignored.
Jabotinsky believed Arab opposition to Zionism was inevitable and that any efforts at reconciliation with Arabs would be unsuccessful. This military force would protect Jewish immigration to Palestine and would allow the goals of Zionism to be achieved. Despite this belief, he still promised that the bourgeois regime that he wanted to take power in the Jewish state would eliminate poverty.
thumb|The party flag of Likud
While the initial core group of Likud's leaders such as Israeli Prime Ministers Begin and Yitzhak Shamir came from Likud's Herut faction, later leaders, such as Benjamin Netanyahu (whose father was Jabotinsky's secretary) and Ariel Sharon, have come from or moved to the "pragmatic" Revisionist wing.
The Revisionist idea of establishing a Jewish homeland over all of the Land of Israel played a role in shaping the ideas of members of Likud.